Try square



P. Lui-Rm TRY-SQUARE Filed Feb; 1,5. 1,9%

R m n M Pfr-EE asm/K m' n?? $11/ a.'

ATTORNEYS Patented Feb. 8, 1944 UNITED STATES PATENT GFFICE TRY SQUARE Peter Lustrik, Cleveland, Ohio Application February 15, 1943, Serial No. 475,918

5 Claims. (Cl. 33-102) This invention relates to improvements in trysquares of the type used by tool and die makers.

The primary object ofthe invention is to provide a square having one side of the stock or head disposed in shouldered relation with the blade ing engagement within the counterbore. j The and the opposed side thereof flush with the outer face of the blade.

Another object of the invention is to provide a supporting structure for a longitudnally adjustable blade which is designed to perform the dual function of locking the blade upon the head and squaring the blade relative thereto.

Another object of the invention is to arrange the clamping screw and blade in contiguous relation with each other so that contemporaneous adjustments thereof can be effected with one hand.

A still further object of the invention is to provide an instrument formed with one face of the head and blade disposed in a common plane and formed to facilitate the use of the tool either as a square or bevel.

Other objects and advantages more or less ancillary to the foregoing and the manner in which all the various objects are realized will appear in the following description, which considered in connection with the accompanying drawing, sets forth the preferred embodiment of the invention.

Referring to the drawing:

Fig. 1 is a front elevational view of the square embodying the present invention;

Fig. 2 is a side elevational view thereof;

Fig. 3l is a vertical section of the square, the section being taken on a plane indicated by the line 3-3 in Fig. l;

Fig. 4 is a view in perspective of the locking screw; and

Fig. 5 is an elevational view of the reverse side of the instrument illustrated in Fig. l, the blade in the figure being of a modied form and being adjusted to show the use of the instrument as a bevel.

Referring first to Figs. l and 2, the improved instrument comprises a head I formed with an undercut step II in the end portion of one face thereof which is machined to a depth equal to the thickness of the blade I2 and of a length equal to the width thereof. In forming the step II the stock is accurately machined so that the ledge or shoulder I3 defined thereby is at right angles with the side walls I 4 of the head. The step I I is drilled and counterbored for the reception of a draw bolt I which is formed with a cylindrical head I6, proportioned for snug slid blade I2 is formed withv a--longitudinal dovetailgroove I'I and an arcuate end portion I8 having a pin I9 therein arranged'for abutting engage ment with the head of the bolt I5 to maintain maximum surface engagement between the blade and the step II when the tool is adjusted for use as a bevel.

The head I6 of the draw bolt is machinedto v provide a lip 20 tapered inwardly for engagement with the inclined flanges 2I of the dovetail groove II. flat faces 22, the body of the head intermediate the faces 22 being proportioned for engagement with the upper edges 23 of the dovetail groove. The draw bolt is further constructed with a threaded shankr 24 for the reception of a thumb nut 25 for locking the blade in seated engage-i ment with the step II.

In the embodiment illustrated in Fig. 5 the dovetail groove I'I terminates in the undercut end wall 26 which serves the function of the stop pin I9.

It will be recognized that as the nut 25 is tightened against the head the parallel faces or lands 22 will prevent the rotation of the draw bolt within the groove I1; that the tapered lip I8 on the bolt will cause the blade to be drawn inwardly against the step II and downwardly against the shoulder I3, and that the blade will thus be drawn into seated engagement with the square shoulder I3.

It will be noted that the outer face 0f the blade and the contiguous face of the head are disposed in a common plane so that the instrument may be used in layout work to scribe, or measure right angles upon a plane surface or burned over and used as a square in the conventional manner. The instrument may likewise be used as a bevel when the layout entails the problem of transferring or measuring angles upon a work piece having a flat surface. The tool may be further used to advantage in layouts where it is necessary to scribe a continuous line on two faces of the work and maintain the line in squared relation with one of the faces; for example, the face I4 of the tool when adjusted for use as a square maybe pressed against the vertical wall of a casting of cubical form, the lower edge of the blade I2 being positioned for engagement with the top thereof. A continuous line may now be drawn upon the top and side walls of the casting by drawing the scribe along the flush faces 2'I-2'I' of the blade and handle.

Although the foregoing description is neces- The head is further formed with parallelv sarily of a. detailed character, in order that the invention may be completely set forth, it is to be understood that the specific terminology is not intended to be restrictive or confining, and that various rearrangements of parts and modications of detail may be resorted to Without departing from the scope or spirit of the invention as herein claimed.

I claim:

1. A try-squarev comprising ahead. having an undercutstepv in the end?. of one face4 thereof dening a ledge disposed at right angles to the sides of the head, a blade in said step engaged with said..

ledge, the outer face of the blade being disposed in a common plane with the face of the head; said blade having a dovetail groove therein, a draw bolt in said head and a taperedlip on the end of said bolt engaged within said dovetail groove for drawing the blade inwardly against the head and downwardly against said ledge.

2, A try-square .comprising ahead, ablade anda1drawf bolt, saidhead. havingga rectangular. step' imtheendthereof of a depth` equalto. the thicknessof; saidlzblade, said. blade. having. a longitudinal-dovetail groove: therein, a head1 on said draw bolt formedtwith a flat. face engaged withf the edgezo. theouter flange dening` said-groove. and a tapered lip on said draw bolt head engaged withthe-inclinedface of the. inner flange definingl said` dovetail groove.

3l Au try-squarecomprising. a head having. a. depressedlstep in-0ne. face thereof', asquare shoulder defined by; said' step, `a-blade having a dovetail"` groove therein. mounted. in said depressed. step with` the. inner; edge thereof" engaged with saidshoulder, vthe outer face ofsaidjblade being. ilushwiththe face ofthe head,. having the steptherein,. a. d'raw Ibolt mounted` in the dovetaili groove in said blade and extended through said head, a nut on said draw bolt, means on the draw bolt to restrain rotative movement thereof and means on the draw bolt to force the blade into intimate engagement with said shoulder when said nut is tightened.

4. A try-square comprising a blade, a head having a step in the end of one face thereof equal in depth to the thickness of said blade and equal in, length. to thewidth ofv the blade, said blade being. mounted in said step. and having a dovetail groove in a face thereof, a draw bolt in said head, a cylindrical enlargement thereon, 'at faces on said cylindrical enlargement disposed in parallel relation with each other, the

dimension of the portion of the bolt between said faces being equal to the groove opening in the facefofthe blade, a tapered lip overhanging one of said. flat faces and engaged within said dovetail" groove, said head having a counterbore therein for theV receptionv and support of; said cylindrical enlargement;

5. A square comprsingga blade, a head., having thenend. portion of. one face thereof; cutaway to a depth equalv to the* thickness. of said blade,v a square. shoulder-ini the head. defined, by the cut away portion thereof, one end of, the blade being ofy semi-circular conguration, said blade. havinga-longitudinal dovetail groove thereinuterminating adjacent the semi-circular` end thereof, a draw bolt in. said` head, atapered lip thereinengaged Within said. groove and a nutonsaicl bolt to facilitate` the impingement4 of.` said blade against said shoulder.. and..the.securement. of the blade` upon.the headin radialadjustment about thebolt.v

PETER LUSTRIK. 

